Dentifrice comprising diatomaceous silica



United States Patent DENTIFRICE COMPRISING DIATOMACEOUS SILICA Alfred Menzies, Los Angeles, Calif.

No Drawing. Application April 3, 1953 Serial No. 346,791

4 Claims. (Cl. 167-93) This invention relates to a dental cleaning and scour ing compound. In modern oral hygiene, in addition to or in place of the usual scouring of teeth by means of dentifrices and brushes, it is recommended that the teeth be also cleaned by means of a scouring and polishing powder usually applied to the teeth by means of some applicator which rubs the teeth. This is commonly a rubber bufier rotated at high speed and usually entails a visit to the dentist.

I have discovered that this technique can be avoided and the cleansing action obtained by the patient and also in his home by the use of a novel cleansing compound and a novel technique for its application to the teeth.

I have found that the use of diatomaceous silica, when of proper purity and particle size, when properly compounded and applied, has such low abrasive qualities as not to scratch the enamel of the teeth or the porcelain or plastics employed in making false teeth and dentures. The compound, however, can, when properly applied, cause a removal of the mucous and salivary plaques which accumulate irrespective of best oral hygiene methods employed, using common dentifrices, employing soaps or other detergents.

I have found that in order to obtain the desired properties to act successfully for the purposes of my cosmetic tooth polish, it is preferable to employ a particular type of diatomaceous silica. The diatomaceous silica which I find preferable is one substantially free of organic matter present in many diatomaceous earths and containing 21 low percentage of materials, other than silica, the contaminants being present preponderately as silicates. The silica is present in the form of diatoms. The material is crushed so that substantially all passes a 325 mesh. The material is a mixed diatomaceous silica which has been heated to about 1800 F. beforehand.

I have found it desirable that the particles be not small for the polishing characteristics. I have found that a particle size distribution which gives less than under 2 microns is a highly useful product.

Without intending to be limited by any theory, it appears that the particular advantage of my polish results from the presence of cellular clumps of individual sharp edge diatoms which are aggregated in the clumps which form the fine mesh particles.

To obtain my superior results, I select the type of diatomaceous silica aggregate which forms the particles so that these particles have a hardness on the Mohr scale of less than tooth enamel. has a value of 7. I select the diatomaceous silica particles which have a value of under 7 and as low as 3.5 to 5.5, for example about 4.5.

I have also found that if the particles used are large, for example, have an average size of about 2 or 3 times that indicated above, the particles are not as useful as dental cleaners. i

Diatomaceous silica is present in many types of diatomaceous earthsor kieselguhrs. The term kieselguhr On this scale, tooth enamel They also contain large amounts of organic material. Such material is not suitable for dental use. lt is gritty and also may have hardness great enough to scratch the dental enamel or injure the gums.

However, l employ selected grades of diatomaceous earths to obtain diatomaceous silica which is substantially free of moisture and organic matter which contains minute traces of contaminants and to obtain a suitable particle size distribution so that the material is suitable for application to teeth. Such a diatomaceous silica should by analysis contain silica in excess of 90% and preferably at least about 93%. A preferred diatomaceous silica, as described below, contains about 94 to 96% SiO In applying the material to the teeth, 1 use an applicator which is softer' than the enamel of the teeth and softer than the diatomaceous silica. The purpose of the procedure found particularly useful is to apply a film of thedental cosmetic to the enamel, applying pressure to -ished dental surface.

desirable that the dental cosmetic of my invention con-' the individual particles against the teeth with a wiping action. Under the influence of this wiping action the diatomaceous silica removes the mucous and salivary plaques present on the teeth, leaving a clean highly pol- Under such conditions, I find it tain no material harder than enamel. Preferably, since I rely upon the action of the diatomaceous silica, 1 prefer that there be no solid material present in the dental composition which is harder than the diatomaceous silica mixture employed. This is particularly important since, in the method of application which I prefer to employ, considerable pressure is exerted against the grains of the powder. The use of hard abrasive grains would result in serious damage to the enamel.

However, I find that not only is it desirable to employ grains of diatomaceous silica substantially free of material having a substantially high hardness on the Mohr scale, for example, hard enough to scratch dental enamel, but I have also found that the particle size of the diatomaceous silica is of critical importance.

I have found that the diatomaceous silica passing a 300 mesh and having a very small percentage, 10% or less, of particles underabout 2 microns by the Oden method are suitable. However, if this fraction is further crushed as by rubbing the powder against a glass plate with a spatula to destroy the aggregates of individual diatoms forming the particles so as to give a substantially impalpable powder, the material'does not act nearly as well as a dental cosmetic and the cleaning action when carried out by the method of pressure application herein described is materially and noticeably decreased.

On the other hand, if I employ a diatomaceous silica the average particle of which is 2 or three times as great, for example, one having particles such that up to 5% will be retained on a mesh (about 15% being greater than 20 microns with about 45% between 10 and 2 microns) it also is found materially less effective than the entire product which passes the 300 mesh screen.

While I do not wish to be bound by any theory of the action of the cleaner, I believe that the efiectiveness of the cleanser derives from the sharp edges of the individual diatoms. These diatoms are held in a cellular structure having the sharp edges. These are produced by grinding mined earth and if the material is ground to too fine a mesh, the sharp edges of the diatoms are destroyed by the grinding action. However, if the particles are too large, then they act like gravel in the mouth and rubbing against the gums injures the gums when pressure is used to apply this material to clean the teeth.

Thus, the use of a diatomaceous earth in particles tine enough north injure the gums and coarse enough so that the sharp edges of the diato'rris have not been destroyed e s ia i si st nr; e e terror sm; th me has bee n ui stc ii hlsv as a s al Newma th'e teethv applying pressure-againsflthe grains on the teeth.:

1h. order toassist in thecleansing1action-,- I find it-desir ablle to in corpoiate entry powdered 8681);! about to- Q% 1 y :rwsight based-on -the diatoma'ceoustsiliea,,for ex--: ample, castile soap, i. e., soapmade from olive oil. This soap; has: antiseptic -quali tiesg-aridg is particularlyz useful in myde ntal xpsrrretier- Qtlier soaps may; be lldg forrexam p1e, .alkali metal soap made trom the otheo wellkno'wrg soagforming: saturated and unsaturated ffatty:-acids;- 'es peciallythose-known to betphysioldgica'lly harmless; for. example the 'stearates andspalmitates; as: well as therole ates? gP-hysiolog-ica-llyharmless wettingqagents may: also be addedv lrpreter-to use a mixturewhich' issn'ot .acidic'and mayadd to the mixture'of soap and :diatomace'ous silica; carbonates such as 'magnesium and lithium carbonate} The" carbonates are attacked' the lacti-c" acid in the: and in the salivary plaque and thus 'act'to-= neutralize the acidity on the teeth and in doingis'o release earbon dioxidwhich-.gives-a mild *frothingl action to aid iri the s'eparatmfl of= the-salivary :plaq-ue' from tlre' teeth; Thedry 'so'ap" powderand the dryrearbtinate':poWdei' also -prevefit -the ca'king of the dental 'cosr'netie -powdfi 'o {the teeth. Without these' 'materials' the powder teaus ta eake up onthetteethy The neutralizing agents suclf as ailtali rntal ei allalihe earth carbonate -e'e'gt sbdihni ate;-= oimagnesium arbona sutures:deserib'eehsl w ihs srse heaaaed rar'isurpsses All-of: these pi'wc'li s htive a hhi'tihess value less'tlilan the diatomaceous silica. I

Flaverixr gmateriais arrayhe seats toiihpart 'a' pleasant taste to the dental co'sinetie; kshitshlefhmmatiuh' for this use is' a folloWs: g r

oiaihmacehss siha; prferahly alfpartictespassing a soo mesh, is grouiidsofthat lessf thaiitjlU% of 'the'material is finer than 2"n'iici'o'us in' size; Tl'luhah ialis'sub Stan-tally anhydrous ehmsihihg its-theme water and hash high watrjahs rpudh and? wt absorb" shout 1; 5' titties as am u'iigli'tof 7 It i hly srdusg 1i resumes-harr rise of heh- 1he su ais'atg the $0.5 content o'iiasubstantially"anhydfoiis'basis in eXce-ss oi" 90%; the matrial othr" than-"slog being. substantiallyiron' and*aluirrinasilicats. I V H V A preferred materialisasfollowsf It 'liasthe ftljlOW- ingc'tiemical"constitution on ash-unearthly moisture free basisi About 94%fsi0ga5eur3't' A1 05; about 1%- Fe O and about 1,5 CC a0 Mg O, K 20 and -l Ia O The material is"t'ree"oforganic material and all sharp or ha'rdparticle's.- Thus it contains-none of thfe fiinh clay, sand or organiti matter'iisuaily. found in lgi'eselguhr or oth'efcrude diatorha'c'eous earths. Particle-sizes all pass through a 325 'meh' screen;

Th'e'ty'pical approximate averageparticlesi-ze distribution of the preferred material is as-follows-z-Coarser than 40 microns, nonerless; than l0 and -more than 6,.-about 12%; less than -6 and morethanlabout &1-%';-less-than 1, about-45%. w 4

Wherever the term particle/size distribution or average particle size is-referred -to ina the":specification an'd claims -it-isunderstood to -meani theta-determined the Oden sedime'n't-at-ion metho'cl -des'fifib ed :ifrxSoil Se-iende} volt l9 (1925) pages] 'to-35:-

lwherever particle-size or-partiele-"size distribution of the diatomaceou's-siliei fl:

4 cation and claims, itis understood to referto the diatg maceous silica before incorporation of the other ingredients of the mixture forming my dental cleaning compound.

With this material I incorporate, by intimate mixing, more than 5% and less than 40% (based on the weight of the diatomaceous earth) of dry powdered castile soap. I have found that 5% or less-ofthe soap makes a product which tends to ca'lte on the teeth and tasteschalky; and 40% of the soap gives a material having a bad odor with a soapy gritty taste. have found that soap powder equal to about 15 73" of th'e diatomaceousear'tliby weight gives a material which does not cakeon: therteeth and does not have an unpleasantoubr: 'onftaste and does not feel gritty.

I may add to thismaterial'abotit"15"to'30% by weight of lithium carbonate and from about 25 to 30% by weight of magnesium carbonate. The carbonate is preferably of= atleast-the -fineness of? the ,diatomaceous. silic'a; 0n

intimate mixture of'these materialsl may add, in addition;

flavoring; agents:

A suitable composition is as follows: Diatomaceousz silica,-2-l grams; MgGG 4 /z g'rams; Li CO 4 /2 grams; castile soap, 3 gramsysaccharine, l gram; 'oil of cassia-,-. 1 /2 c'e.-; ;oil of peppermintg /accgoil of Wintergreen,- licc.

This material is-dntirnatelyj mixed, Thepowde'r tends: to ball up into small aggregates bound by; the added oils,-.

butttheaggregates are very: friable, eve'n morer's'o than the diatomac-eous earth particles;

about 200 or 300 mesh by this procedure. a v

Iii-applying this=material,' thepowdereis 'pushed up by an applicator and conveyed "to the teeth. For example, I- use? 'a roll of cottonbatting similar to a chum dental '1 roll The/end of the roll, slightiyrrrdistn'ed,is dipped" in the p'owder 'ar'id thefpo'wder carried to the -teeth.- The coated end ofthe'roll is' rubbedacrass'the'teeth with ato and fro motion: without using 'any' fluid oth'ei-than the natural saliva iii the" mouth "which may aceidentall y iget' i Insteachthe powder mayb'e' applied with:

onrthe teeth: a rubber bufi'ing cup such as used by dentists' when they polish the'teeth with pumice.

In both cases the'applic'ator 'a'pplies'a considerable pressure against the p'o'wder'on the teeth. It is for this reason that'it is important that the material have a hardness value 'such that-it will n'ot-seratchthe enamel but be hard enough to cut throiigh -the salivary mucous plaque; or what." is rnrdre' g'eaeiaIly*referred to as stain and tartar on' the' teethtv When-"s6 usee' theteth are c'lean, polished; a'ndbefcause "otzrhe high poli'sl'i 'the attachmentto the teeth of soil and:'ea lcar'euus deposits which build tartar i moredifficult and 't-he te'eth appear-ahdfe'el smooth, slick; andsiloxaues, such as, for example, the 'alltyl'siloxanes; m1

siloxan'es'; for 'eiatr'rp'le, the aryl alkyl siloiraneshave' the ro ertyer ihcreasiiig the tooth polish which may be obtaineel arid the teeth remaih cleaner and unstained for the cleansing action, silicone oilisidposited'jo'nfthe teeth by' trahfiaene'e o'ti nte ests to imp'a "a u If desired they. may forced through-fine meshed screens about 200 mesh and? the a-g'gregates will beseparated into fine particles of" I may use the siloxanes produced by hydrolysis of dimethyl dichloro silane or diethyl dichloro silane or the hydrolysis of diethyl dialkoxysilane.

The preferred oil, because of its utility in my material and its physiologically harmless quality when used in a dental cleanser, is the methyl silicone oil made by hydrolysis of dimethyl dichloro silane or trimethyl dichloro silane or mixtures thereof to give the methyl silicones. This is believed to be the material sold by the General Electric Company and named G. E. Silicone SF series. I prefer to use this oil and to employ the lowest viscosity material of centistokes at 100 F. This material has a specific gravity 20/20 C. of 0.964. I may, however, use higher viscosity oils which will adequately mix with the powder. If too viscous the oils may be diluted with suitable physiologically harmless diluents, as will be understood by those skilled in the art.

I may use this material, preferring not to use so much of it as to give a greasy or mushy powder but rather one that appears dry. Thus, I may use with the last mentioned composition given above about 5 to 15 cc. of the silicone oil, a suitable amount being cc. Similar quantities of the material may be added to the compositions described above, i. e., from about 25 to 75% of the silicone oil by weight based on the diatomaceous silica. The silicone oil is added after incorporating the other ingredients, i. e., at the last, so that the grains of the powder are coated by the silicone.

While I have described a particular embodiment of my invention for the purpose of illustration, it should be understood that various modifications and adaptations thereof may be made within the spirit of the invention as set forth in the appended claims.

I claim:

1. A dental cleansing composition, comprising a major portion of diatomaceous silica and a minor portion of a dry powdered soap, said silica being pure to the extent of containing in excess of 90% Si0 said silica having a particle size distribution such that the entire silica will pass a 300-mesh screen and not more than about 10% thereof has a particle size of under 2 microns, all the ingredients of said composition having a hardness value less than dental enamel.

2. A dental cleansing composition as defined in claim 1, said dry powdered soap being present in amount by weight of approximately from 5% to of the diatomaceous silica.

3. A dental cleansing composition as defined in claim 2, and further including carbonate salt chosen from the group consisting of the alkali metal and alkaline earth carbonates in an amount by weight of approximately from 5% to 30% of the diatomaceous silica.

4. A dental cleansing composition as defined in claim 3, and further including silicone oil in amount by weight of approximately from 25% to of the diatomaceous silica.

References Cited in the file of this patent UNITED STATES PATENTS 908,131 Potter Dec. 29, 1908 1,467,024 Bergve Sept. 4, 1923 1,627,446 Moseley May 3, 1927 2,059,396 Ripert Nov. 3, 1936 2,222,969 Kistler Nov. 26, 1940 2,550,207 Tainter Apr. 24, 1951 FOREIGN PATENTS 633,845 Great Britain Dec. 30, 1949 686,429 Great Britain Jan. 21, 1953 OTHER REFERENCES U. S. Dispensatory, Wood, 22d ed., 1937, pp. 1101- 1103.

Drug and Cos. Ind. (Thomssen), December 1944, p. 673. 

1. A DENTAL CLEANSING COMPOSITION, COMPRISING A MAJOR PORTION OF DIATOMACEOUS SILICA AND A MINOR PORTION OF A DRY POWDERED SOAP, SAID SILICA BEING PURE TO THE EXTENT OF CONTAINING IN EXCESS OF 90% SIO2, SAID SILICA HAVING A PARTICLE SIZE DISTRIBUTION SUCH THAT THE ENTIRE SILICA WILL PASS A 300-MESH SCREEN AND NOT MORE THAN ABOUT 10% THEREOF HAS A PARTICLE SIZE OF UNDER 2 MICRONS, ALL THE INGREDIENTS OF SAID COMPOSITION HAVING A HARDNESS VALUE LESS THAN DENTAL ENAMEL. 